25 research outputs found

    Extraction of the electron mass from gg factor measurements on light hydrogenlike ions

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    The determination of the electron mass from Penning-trap measurements with 12^{12}C5+^{5+} ions and from theoretical results for the bound-electron gg factor is described in detail. Some recently calculated contributions slightly shift the extracted mass value. Prospects of a further improvement of the electron mass are discussed both from the experimental and from the theoretical point of view. Measurements with 4^4He+^+ ions will enable a consistency check of the electron mass value, and in future an improvement of the 4^4He nuclear mass and a determination of the fine-structure constant

    High-precision mass spectrometer for light ions

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    The precise knowledge of the atomic masses of light atomic nuclei, e.g., the proton, deuteron, triton, and helion, is of great importance for several fundamental tests in physics. However, the latest high-precision measurements of these masses carried out at different mass spectrometers indicate an inconsistency of five standard deviations. To determine the masses of the lightest ions with a relative precision of a few parts per trillion and investigate this mass problem, a cryogenic multi-Penning-trap setup, LIONTRAP (Light-Ion Trap), was constructed. This allows an independent and more precise determination of the relevant atomic masses by measuring the cyclotron frequency of single trapped ions in comparison to that of a single carbon ion. In this paper the measurement concept and a doubly compensated cylindrical electrode Penning trap are presented. Moreover, the analysis of the first measurement campaigns of the proton's and oxygen's atomic mass is described in detail, resulting in mp=1.007276466598(33)u and m(16O)=15.99491461937(87)u. The results on these data sets have already been presented by F. Heiße et al. [Phys. Rev. Lett. 119, 033001 (2017)]. For the proton's atomic mass, the uncertainty was improved by a factor of three compared to the 2014 CODATA valu

    Image charge shift in high-precision Penning traps

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    An ion in a Penning trap induces image charges on the surfaces of the trap electrodes. These induced image charges are used to detect the ion's motional frequencies, but they also create an additional electric field, which shifts the free-space cyclotron frequency typically at a relative level of several 10 −11. In various high-precision Penning-trap experiments, systematics and their uncertainties are dominated by this so-called image charge shift (ICS). The ICS is investigated in this work by a finite-element simulation and by a dedicated measurement technique. Theoretical and experimental results are in excellent agreement. The measurement is using singly stored ions alternately measured in the same Penning trap. For the determination of the ion's magnetron frequency with relative precision of better than 10 parts per billion, a Ramsey-like technique has been developed. In addition, numerical calculations are carried out for other Penning traps and agree with older ICS measurements.peerReviewe

    High-Precision Measurement of the Proton’s Atomic Mass

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    We report on the precise measurement of the atomic mass of a single proton with a purpose-built Penning-trap system. With a precision of 32 parts-per-trillion our result not only improves on the current CODATA literature value by a factor of three, but also disagrees with it at a level of about 3 standard deviations

    g Factor of Lithiumlike Silicon: New Challenge to Bound-State QED

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    The recently established agreement between experiment and theory for the gg factors of lithiumlike silicon and calcium ions manifests the most stringent test of the many-electron bound-state quantum electrodynamics (QED) effects in the presence of a magnetic field. In this Letter, we present a significant simultaneous improvement of both theoretical gth=2.000 889 894 4 (34)g_\text{th} = 2.000\,889\,894\,4\,(34) and experimental gexp=2.000 889 888 45 (14)g_\text{exp} = 2.000\,889\,888\,45\,(14) values of the gg factor of lithiumlike silicon 28^{28}Si11+^{11+}. The theoretical precision now is limited by the many-electron two-loop contributions of the bound-state QED. The experimental value is accurate enough to test these contributions on a few percent level.Comment: 5 pages, 1 figur
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